Energy absorbing foams based upon urethane chemistry are known in the art,. The early literature generally utilized halocarbon blowing agents (see, e.g., U.S. Pat. No. 3,926,866). A significant number of patents have issued relating to water blown energy absorbing foams based upon polyols ("filled polyols") prepared by polymerizing styrene/acrylonitrile monomer mixtures in polyethers (see, e.g., U.S. Pat. Nos. 4,116,893, 4,190,712, 4,212,954, 4,866,102, 5,216,041 and 5,232,957). Other patented technology describes the use of relatively low molecular weight crosslinkers (see, e.g., U.S. Pat. Nos. 4,282,330, 5,143,941, and 5,167,884) or the use of various polyols, such as ethylene oxide adducts of Mannich condensates (U.S. Pat. No. 4,371,629), alkoxylated toluene diamine (U.S. Pat. No. 4,614,754), or polyols derived from propylene glycol or ethylene diamine (U.S. Pat. No. 5,187,204).
While systems based upon some of the patents noted above have been used commercially, the search continues for systems which will produce energy absorbing foams which will meet a variety of specifications such as Ford specification WSB-M2D403-A3 for side impact, and which also meet commercial production processing requirements of 12 second mold closing and 3 minute demold. "Mold closing" is defined as the time from the start of the introduction of the foamable reactants into the mold until the mold is closed. "Demold time" is defined as the time from the start of the introduction of the foamable reactants into the mold until the finished part is removed from the mold.